Each month, ELLE.com wades through the style blogosphere in search of just the right guest blogger—or in this month's case, guest bloggers—to post regularly on our site's Dispatch blog. In honor of our June Body Issue (starring Kerry Washington), we tapped Alexia Brue and Melisse Gelula, the founders of WellandGoodNYC.com, who'll bring us their fitness and nutrition expertise. Every Wednesday for the next four weeks, you'll find a roundup of workout and wellness trends courtesy of Alexia and Melisse. And, for a healthy end-of-week treat, they'll be posting a new smoothie recipe each Friday. For even more tips and recipes from the Well+Good gals—and much, much more—check out the June issue of ELLE on newsstands now.

Seamless spandex is the fitness fashion world's new favorite fabric. It's suddenly being used in cute crops and lean tanks by indie brands like Phat Buddha, Electric Yoga, and Ellie—and even major players like Lululemon. The material doesn't squeeze and compress, allowing its wearers the freedom to move from lunge to squat—pun intended—seamlessly. While seamless's nylon-Spandex allure is partially aesthetic—the finish is an elegant matte and comes in an array of textures, like perforations—it's also super comfortable, thanks to its thin, low-seam construction. (Carbon38 co-founder Caroline Gogolak said, "it can be very soft and comfortable, and it's not constricting. A lot of people like that.")

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All that said, with seamless's innovations come some technical trade-offs. We sweated in seamless during a handful of different workouts and tapped Phat Buddha designer Alissa Benishai for her fabrication expertise to bring you this list of the fabric's pros and cons:

The One Size Fits All Factor

Pro: Alissa Benishai, the creator-designer of Phat Buddha in New York—who's outfitted fitness celebs from cardio dance queen (and Gwyneth BFF) Tracy Anderson to Lady Gaga's yoga instructor Tricia Donegan—says it appeals to regular women "because they can wear it at any stage in life—super skinny, prego, bloated, or just average weight."

Con: We wore it to Barry's Bootcamp and had to yank up the bottoms while on the treadmill, and during an hour-long cardio-fitness class we noticed the tank riding up about 15 minutes in. Our takeaway: Because this fabric moves—the pants down and the shirts up—buy your tanks long-waisted and your pants high-waisted.

The Wear-And-Tear Test

Pro: It does stretch out, but when you wash it, it comes right back to size.

Con: There are a range of seamless fabrics, from thicker to show-every-tush-dimple thin, and it can be hard to know which you're getting from the get-go.

Con: It's not supportive. It won't help suck in your belly or boost and lift your booty. So seamless isn't great for looking like a fitness model or an athlete unless you are one. "Some people want more of a constricting fit that will suck everything in, and some people don't," says tech-advisor Gogolak. "It's all about what works for your body."